Load break interrupter



Oct. 29, 1957 G. L. ATKINSON LOAD BREAK INTERRUPTER Filed Feb. 23, 1956ATTORNEY Unite States Patet LOAD BREAK INTERRUPTER Gerald L. Atkinson,North Chili, N. Y., assignor to McGraw-Edison Company, a corporation ofDelaware Application February 23, 1956, Serial No. 567,263

4 Claims. (Cl. 200-144) This invention relates to improvements in a loadbreak interrupter for use in electric circuits.

The load break device herein disclosed is intended primarily for use incombination with a circuit breaker in substantially the same manner asdisclosed in my copending application Serial No. 427,557, filed May 4,1954, for Circuit Interrupter Devices and issued as Letters Patent No.2,785,254, March 12, 1957. The device herein disclosed momentarilycarries the full load of an electric line after the circuit breaker hasbeen operated to open position and then quickly interrupts the loadwithin the confines of an expulsion chamber thereby avoiding damage toconductive parts of the circuit breaker.

An object of this invention is to provide in an interrupter, a pair ofarcing contacts which are rapidly separated to draw an are into anexpulsion chamber prior to movement of the interrupter to open circuitposition, the interrupter then moving to open circuit position under thecontrol of the circuit breaker.

Another object is to provide a pair of arcing contacts which areseparated relative to each other with a snap action movement to draw anare into an expulsion chamber.

A further object is to provide an interrupter in which the arcingcontact is moved into an expulsion chamber with a snap action prior tomovement of the interrupter to full open position and in which thearcing contact is automatically returned to closed position with a snapaction movement when the interrupter is in open position.

It is also an object to provide for a load break interrupter, arcingcontacts which when separating draw an are between areas thereondisposed at points oifset from the normal contact areas, therebyavoiding damage to the contact areas when the contacts are separated.

In the drawings:

Fig. l is a longitudinal sectional view of the interrupter as it appearswhen the circuit breaker is in either closed or full open position.

Fig. 2 is a similar view showing the relative position of the elementsimmediately preceding load breaking operations after the circuit breakeris disconnected.

The interrupter herein disclosed embodies a hinge member comprising asleeve 11 having a threaded aperture 12, a threaded annular boss 13, anda pair of substantially parallel pivot arms 14 each provided with apintle 15 pivotally mounted intermediate the ends of a pair of parallelcircuit breaker bars (not shown). A tube 16 of insulating material, isthreaded at one end into the threaded aperture 12 and is provided at theopposite end with a metal ferrule 17 having an aperture 18 concentricwith the tube.

The tube 16 has a bore 19 terminating in a shoulder 20 adjacent to asmaller bore 21. Fitting snugly within the bore 19 is an insulatingsleeve 22 composed of a material which, under the influence of heat,will generate or emit an arc extinguishing gas. The inner diameter ofthe sleeve 22 is substantially the same as that of the bore 21. Asindicated, the diameter of the aperture 13 ice in the ferrule 17 is suchas to provide an annular shoulder projecting inwardly of the bore 21.

A metallic tube 25 having vents 26 is threaded on the base 13 on thesleeve 11. A closure cap 27 is threaded on the upper end of the tube 25and is provided with a centrally recessed portion 28 which receives asecond metallic tube 29 extending to and engaging the upper end of thetube 16. The tube 29 is provided with a multiplicity of ventingapertures 30. Secured to the exterior of the tube 29 by any suitablemeans, such as a rivet 31, is a resilient conductive strip 32 having itsupper portion 33 projecting angularly into the interior of the tube 29through an elongated aperture 34 and terminating in an arcuate latchingend 35. The opposite end portion 36 of the strip 32 is provided with acontact block 37 secured thereto and positioned in a slot 38 to extendinto the tube 29. For reasons which will be later apparent, the block 37is beveled at 39.

The load break mechanism is mounted within the tubes 16 and 29 and ismovable longitudinally thereof. This mechanism comprises an insulatingrod 45 embodying arc extinguishing material, such as Lucite, a metallicrod 46 secured to the lower end of the insulating rod and having acylindrical contact block 4'7 secured thereto adjacent the rod 45, and ametallic sleeve 48 surrounding the rod 46 and movable longitudinallythereof.

The upper end of the insulating rod 45 is provided with a latch member50 secured thereto and having an annular groove receiving the latchingend 35 on the resilient strip 32. intermediate the ends of the metallicrod as is an enlarged cylindrical portion 51, the function of which willhereafter become apparent. The lower end of the rod 46 is flanged at 52.The upper end of the metallic sleeve 48 is closed by an apertured cap 53secured thereto in any suitable manner, such as welding and slideable onthe rod 46. This cap is cylindrical and projects beyond the sleeve 48 toprovide an annular shoulder.

The lower end of the sleeve 48 is capped by a latching member 54 havingan annular groove 55 for receiving biased contact prongs (not shown). Anexpansion coil spring 6%), surrounding the rod 46, is positioned withinthe sleeve 48 and engages the flange 52 on the rod 46 and cap 53 on thesleeve 48. A second expansion spring 61 is positioned within the tube16, surrounding the sleeve 48, and engages the cap 53 on the sleeve 48and the flanged portion on the ferrule 17.

Normally, the springs 64) and 61 bias the elements of the load breakmechanism to the relative positions illustrated in Fig. 1. When theserelative positions prevail, the ioad break mechanism will be in eitheropen or closed circuit positions relative to an electric line. Assumingthat the mechanism is in closed position, then current will flow fromthe cap 54 to the pintles 15 through the sleeve .8, cap 5'3, spring as,rod 46, contact blocks 47 and 37, strip 32, tube 29, tube 25, sleeve 11and arms 14.

Assuming again that the load break mechanism is pivotally mounted on apair of spaced circuit breaker bars, as in my aforesaid Letters PatentNo. 2,785,254, then operation of the circuit breaker to open positionwill cause the sleeve 4-8 to recede from the tube 16, as indicated inFig. 2, by reason of the latched engagement of the cap 54 with a jawcontact (not shown).

As the sleeve 4% is withdrawn from the tube 16, it wiil, through themedium of the cap 53 at its upper end, compress the springs as and 61.Continued movement of tube 48 outwardly of the tube 16 will engage thecap 53 with enlarged cylindrical portion 51 on the rod 46 at which timethe rod 46 will move with the sieeve 48 and withdraw the latch member 5%at the upper end of the 37 is beveled at one corner.

3 rod 45 from engagement with latching end 35 on the strip 32.

When the latch member 50 and latching end 35 are disengaged, the spring60 takes over and separates the contact blocks 37 and 47 by moving thecontact block 47 downwardly into the insulating sleeve 22 with a snapaction movement, thus extending an are between the contact blocks andsubjecting the arc to an arc extinguishing material evolved by heat ofthe are from the sleeve 22.

Subsequent to extinguishment of the arc, further movement of the sleeve48 outwardly of the tube 16 will be opposed by the compacted spring 61and compel the latching cap 54 to disengage the jaw contacts (not shown)whereupon the spring 61 will be released and, with a snap actionmovement, return the various movable elements to the relativerelationship shown in Fig. 1.

It has previously been noted that the contact block It will now be notedthat the cylindrical contact block 47 is provided with a tapered endadjacent the insulating rod 45. When the contact blocks 37 and 47 areseparated in the manner previously described, the are establishedbetween them will play on beveled surface of the contact block 37 andthe tapered end of the contact block 47, rather than between the contactsurfaces of the blocks, thus avoiding burning and mutilation of thecontact surfaces during load break op eration.

Preferably the sleeve 22 and rod 45 are composed of materials which willevolve an arc extinguishing material in the presence of an are. When therod 45 is being drawn into the sleeve 22, an are established between thecontact blocks 37 and 47 will be confined between the opposing surfacesof the rod and sleeve and the heat of the arc will cause arcextinguishing material to be evolved. To avoid pressure build up due toevolution of the arc extinguishing gases, the cylinder 29 is aperturedat 30 to permit expansion into the space between the cylinders 29 and 20and outwardly of the cylinder 20 at the openings 26.

Due to the fact that the cylinders 20 and 29, particularly cylinder 26,expose considerable surfaces to the hot gases and quickly reduce thetemperature thereof, so that, in actual practice, the volume of gasesescaping from the openings 26 in the cylinder 26 is considerably reducedfrom that generated in the presence of an arc.

From the foregoing it will be apparent that a novel load breakinterrupter has been disclosed, which provides a snap actioninterruption of electric circuit and extinguishment of an arc prior tomovement of the interrupter to open circuit position and which,subsequent to movement of the interrupter, provides a snap action returnof the load interrupting mechanism to its normal position for subsequentload interrupting operation.

It will also be apparent that a novel arrangement of arc interruptingcontacts has been provided which, on separation of the contacts,disposes an arc therebetween at points thereon remote from the contactsurfaces, thus avoiding burning and damage to the contact surfaces.

I claim:

1. In a load interrupter for an electric circuit, the combination withan insulating tube and a vented electrically conductive tube projectingfrom one end of and concentrically secured to said insulating tube, of aresiliently supported contact including a latch member projecting intosaid conductive tube, a cap secured to the other end of said insulatingtube and apertured centrally thereof to provide an annular shoulderinward of said insulating tube, an elongated conductive sleeveprojecting into said insulating tube through the aperture in said cap, aconductive latching contact closing the outer end of said sleeve andnormally positioned adjacent said cap, a centrally apertured annularclosure member closing the inner end of said sleeve and providing anannular shoulder radially of said sleeve and normally positioned at thejuncture line of said insulating and conductive tubes, a first expansioncoil spring in said insulating tube and surrounding said sleeve, saidfirst spring engaging said annular shoulders on said cap and saidclosure member thereby biasing said sleeve inwardly of said insulatingtube and maintaining said latching contact and closure member in saidnormal positions, a conductive rod projecting into said sleeve throughthe aperture in said closure member, a contact secured to said rod andnormally adjacent said closure member exteriorly of said sleeve andelectrically engaging the first mentioned contact, a flange on said rodand positioned in said sleeve remote from said closure member, said rodhaving intermediate its ends an enlarged element engageable with saidclosure member, a second coil spring within said sleeve and surroundingsaid rod, said second spring engaging said flange and closure member andnormally biasing said rod inwardly of said sleeve to normally maintainsaid second contact adjacent said closure member, and latching meanscarried by said rod normally releasably engaging said latching member insaid conductive tube.

2. In a load interrupter for an electric circuit, the combination withan insulating tube having exteriorly thereof at one end a stationarycontact and latching means, of a sleeve extending into said tube fromthe other end thereof and having a latching contact exteriorly of saidtube at said other end, said sleeve extending substantially the fulllength of said tube when innormal position, a rod extending into saidsleeve from said one end of said tube and having contact normallyengaging said stationary contact and having a latch member normallyengaging said latching means, said rod extending substantially the fulllength of said sleeve, a first expansion spring in said sleeve andsurrounding said rod, one end of said first spring engaging said sleeveat the end thereof adjacent said one end of said tube, the other end ofsaid spring engaging said rod at a point thereon most remote from saidcontact, a second expansion spring in said tube and surrounding saidsleeve, one end of said second spring engaging the end of said sleeveadjacent said one end of said tube and the other end of said secondspring engaging said tube ad jacent said other end thereof, andinter-engageable means on said rod and sleeve effective to move said rodsimultaneously with said sleeve subsequent to a predetermined relativemovement therebetween.

3. In a load interrupter for an electric circuit, the combination withan elongated insulating member having at one end a stationary contactand latching means, of an elongated actuator carried by and movablelongitudinally of said member, a movable contact normally engaging saidstationary contact and including a latch releasably engaging saidlatching means, said movable contact and latch being movably mounted onsaid actuator, a first spring on said actuator having one end inengagement therewith and the other end in engagement with said movablecontact, a second spring on said insulating member having one endthereof in engagement with said member and the other end thereof inengagement with said actuator, and means adapted to interengage saidactuator and latch subsequent to a predetermined relative movementtherebetween, whereby energy accumulated in said springs releases saidlatch and affords a snap action separation of said contacts andthereafter returns all movable elements to their normal positions forcircuit closing operations.

4 In a load interrupter for an electric circuit, the combination with aninsulating support having a stationary contact, an actuator movablysupported by said support, and a contact carrier movably supported bysaid actuator and having a second contact normally engaging saidstationary contact, releasable latch means normally holding said carrierimmobile, inter-engageable means on said actuator and carrier operativesubsequent to a relative predetermined movement therebetween to effectsimultaneous movement thereof whereby to release said latch means, andspring means normally maintaining actuator and carrier immobile relativeto said support and to each other, said spring means accumulating storedenergy on movement of said actuator and quickly separating said contactsupon simultaneous movement of said actuator and carrier and thereafterreturning said actuator and carrier to their positions normallymaintained by said spring means.

References Cited in the file of this patent UNITED STATES PATENTSHeinrich Oct. 18, 1921 Allan Sept. 1, 1931 Seaman Sept. 8, 1936 SkeatsJuly 20, 194-8 Driescher Feb. 9, 1954

